The research proposal is designed to elucidate the molecular structure of the synaptonemal complexes in mouse spermatocytes. These intricate structures, ubiquitous in mammalian species, are responsible for the pairing of homologous chhromosomes during meiotic prophase. A procedure has been developed to isolate intact synaptonemal complexes as integral components of nuclear matrices prepared from isolated populations of pachytene spermatocytes. The nuclear synaptonemal complex matrix (SCM) is comprised of protein (approximately 96%), DNA (approximately 2%), and RNA (approximately 2%). The isolated SCM will be subjected to detailed morphological characterization, using both light and electron microscopy of whole mount preparations. Polypeptide and glycoprotein constituents of the SCMs will be analyzed in detail using radiolabeling techniques and SDS-, acetic acid-urea-, and two dimensional-polyacrylamide gel electrophoresis followed by autoradiography. The SCM preparation, or a detergent-extracted version, will be used as immunogen to elicit xenogeneic antibody production in female rats. Monoclonal antibodies isolated by the interspecies hybridoma technique are then to be used for further characterization of the molecular structure of the synaptonemal complexes. This will involve preparing protein A-conjugates with fluroescein, rhodamine, ferritin or colloidal gold. These fluorescent and electron dense probes will be used to microscopically localize the respective antigenic determinants to specific components or regions of the synaptonemal complexes. Moreover, studies on the synthesis and assembly of the synaptonemal complex during meiotic prophase will be investigated by applying the monoclonal antibodies in solid phase radioimmunoassay and morphological techniques. Finally, selected polypeptide constituents of the synaptonemal complexes are to be isolated and characterized biochemically.